So you've decided you're going to get a portable GPS device, but what features should you look out for and which brand is best at what?

Screen size
As far as displays go, bigger is generally better, although the clarity and aesthetic appeal of the on-screen graphics play a big part too — more of that later. In the portable GPS market — or personal navigation device (PND) in marketing speak — there are two screen sizes: 3.5-inch and 4.3-inch.

3.5-inch screens are only seen nowadays on entry level and carry over models. If you can afford the AU$50 or AU$100 price hike required to jump up to a 4.3-inch model, we'd highly recommend it. The extra screen width improves map viewing and allows for a larger virtual keyboard. Most PND screens have the same resolution — 320x240 on 3.5-inch screens and 480x272 on 4.3-inch models. There are some exceptions though, like the Garmin Nuvi 5000 and the discontinued HP iPAQ 312 Travel Companion.

User interface
A question that we're always asked at CNET Australia is which GPS has the best interface. We usually follow up with a whole bunch of questions, like "is ease of use paramount?" and "are looks important?". To which the person asking the question will tell us to stop using questions as a form of response, before demanding that we answer the first question. At which point we'll say "either TomTom or Garmin" and then sulk in the corner.

Both Garmin and TomTom feature easy to use menus, simple map screens and are, in our opinion, the quickest to get the hang of. Like the Windows versus Mac OS debate, we're sure that some of our users will disagree violenty but, like the aforementioned operating systems, once you've become so accustomed to one system's particular quirks it's hard to jump ship.

Maps
Until mid-2008 all brand name portable GPS devices came with maps from Whereis — the mapping service owned by Telstra's Sensis directory arm, which incidentally owns both UBD and Gregory's. The latest version of the Whereis maps was released in late-2008 and is often referred to as R15.1.

Navteq — a wholly owned subsidiary of mobile phone maker Nokia — has this year muscled its way into the Australian market snaffling up contracts to supply maps to Mio, Navman and Navigon, amongst others.

Windshield mounts
Unlike some of the other features you'll see in this article, windshield mounts get nary a mention in advertising material. Sexless they may be, but they're critical in one's day-to-day use of a GPS. Most units are affixed to a windscreen via a suction cup with an attached lever, which provides the extra suction required to withstand potholes and other road blemishes.

TomTom's second-gen XL and fourth-gen One feature the most innovative windshield mounts we've seen to date. The mount is attached to the GPS unit's circular speaker, while the suction cup is operated via a twist ring rather a conventional lever. This design not only folds up compactly — great for those with small gloveboxes or too much junk — but looks great too.

On the flipside the same company also offers the least secure window mounts available today on its Go 730 and Go 930 models. Interestingly, these more expensive models — the Go 930 Traffic is close to a grand — use an older design that doesn't include a lever. As a consequence the Go 730 and Go 930 wobble like a bobble-head toy after too much red cordial and sometimes send the GPS crashing into your dashboard if you hit a pothole or drive over a speed hump with a bit too much vim.

Another dishonourable mention goes out to the windshield cradle seen on the Mio Moov range and the Navman S35 and S45. With these units you have to align both a tongue and the mini-USB port, a feat which we described as being akin to splitting atoms with a toothpick.

Traffic alerts
All the major brands (Mio, TomTom, Garmin and Navman) offer, both as pre-bundled packages and as an optional extra, traffic messaging in their lineups. Despite sounding like it would send you a whole bunch of SMSes, a GPS unit with traffic messaging can either warn you of traffic incidents along your current route, automatically re-route around severe traffic delays, or both. You can also use your traffic-enabled GPS device to look up jams, road works, special events and so forth before heading off on your journey.

Traffic messaging is currently available in Sydney, Melbourne and Brisbane, with Perth, Adelaide and Canberra scheduled to get services in sometime in 2009.

Check out our GPS Traffic Messaging FAQ for more information.

Text-to-speech or spoken street names
Most of the new GPS models introduced in 2008 feature text-to-speech. Nowadays often marketed using the less technical moniker of spoken street names, or something similar, this feature allows the GPS to say aloud road names as part of its spoken instructions. This means instead of hearing just "turn left in 500 metres", you might hear something like "turn left in 500 metres on to Liverpool Road".

Anyone who's ever studied English as a second language, or helped someone study it, will know that pronounciation-wise it's pretty irregular. Consider the many ways that the four letter combination "ough" can be pronounced depending on the word — bought, cough, though, through and thorough are just a few of the possible sounds produced by those four little letters. Consider then that proper names are, if anything, even more irregular.

Mix this in with the Aussie accent and our frequent use of Aboriginal words in street and road names, and you'll come to an understanding as to why GPS devices have such a hard time getting the words out right. Some of the more memorable mispronounciations we've heard over the years have include Bourke Street being uttered as Bork Street, Wattle Street as What-lah Street and Illawarra Road as, well, something close to Swahili.

With the adoption of Navteq maps in the latest Mio Moov, Navman S-Series Platinum and Navigon ranges, things have taken a turn for the better. The Navteq maps include phonetic information for street names, meaning that pronounciation is better. It's not infallible, however, and the accent is sometimes off the mark too.

Lane guidance
Up until mid-2008, GPS units sold in Australia only told you whether to turn left or right, or continue straight. Important information, to be sure, but sometimes it's just as important to know which lane you're meant to be in. Some of this year's GPS new units, such as Navigon's 2150max, as well as Navman's S-Series Platinum range, offer lane information at major intersections. At some of these a full-screen 3D graphic, with lane info and street signs, will replace the regular map.

So far the best lane guidance we've seen has been on TomTom's Go 730, and by extension the Go 930. On these units, lane guidance is given on most of the major roads and streets, not just major intersections.

Safety cameras
Most of the GPS devices launched in 2008 feature warning alerts for speed and red light cameras. These alerts usually consist of a generic warning tone and a flashing icon, small or large, somewhere on screen. The alerts on Garmin's Nuvi 260W and 760 are a cut above this though, offering a detailed verbal warning instead of the normal generic tone, as well warnings for school zones. Unfortunately the company makes you jump through some hoops to get at them.

School zone warnings are also featured in all the new Navteq-equipped GPS units — the Mio Moov, Navman S-Series Platinum and Navigon ranges. However on these systems, the school zones seem to be defined as a radial zone around a particular school, rather just on the roads with traffic restrictions. As such, you can be driving along a major road and be warned about a school several streets away — we were once even warned of a school zone on a motorway! This is not only annoying but can lead to drivers ignoring all camera warnings thrown up by a GPS.

Additionally, one shouldn't rely on your GPS to warn you about every speed, red light and school zone camera. Sometimes manufactuers misplace or omit cameras by accident, and road authorities are always keen to put up more of these tax-collectors-cum-safety-contraptions.

Bluetooth hands-free
Most mid to high end GPS units nowadays feature mobile phone hands-free via Bluetooth. While voice quality is sufficient in most for a quick a chat, or to let friends and family know that you're running late, don't expect them to be up to snuff for longer discourses. You may also want to ensure that your phone's Bluetooth is supported by the GPS you're intending to buy — either check out the manufacturer's website or try it in store before purchasing.

FM transmitter and MP3 playback
Many higher end GPS offer MP3 playback and an FM transmitter — the former is of little use without the latter because the tinny speaker on all GPS units does little justice to music, even if it's just Natalie Bassingthwaighte. The FM transmitters on some devices, such as the Navman S300t and the superceded TomTom Go 720, were so weak and meek that a pirate radio station located in Ursa Minor would overpower them.

If music playback via your GPS is a priority then our pick would be Garmin's Nuvi 760. Its transmitter not only has sufficient power to work well in the CBD, but it's also one of the few GPS devices we've tested that's happy to read music files straight off an SD card.

About the author

Derek loves nothing more than punching a remote location into a GPS, queuing up some music and heading out on a long drive, so it's a good thing he's in charge of CNET Australia's Car Tech channel.
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